An internal combustion engine (e.g., a diesel engine), can be provided with a ventilation system for venting the fumes that leak past the piston rings and through the circulating oil in the crankcase. The crankcase fumes (i.e., a mixture of air, exhaust, and oil) are commonly passed through a filter assembly. Such a filter assembly can include, for example, an inlet chamber, an outlet chamber, and a filtering media (through which the crankcase fumes must pass to flow from the inlet chamber to the outlet chamber) that removes particulates and other contaminants. Oil will typically migrate through the media with the gas, and oil droplets will form on the filter surface within the outlet chamber. Gravity causes the oil droplets to slide downward and a bottom receptacle can be positioned for collection thereof.